Process for forming a composite Ni and Cu alloy plating film

Abstract

A composite nickel and copper alloy plating film ( 3 ) containing nickel and copper. Nickel is of high wear resistance and a nickel alloy improves the wear resistance of the film. Copper is of high corrosion resistance and a copper alloy improves the corrosion resistance of the film. The film may further contain self-lubricating particles and hard particles which ensure its wear resistance and lubricating property to a further extent.

1 - 11 . (canceled)  
   
   
       12 . A process for forming a composite nickel and copper alloy plating film on a base surface, comprising the steps of: 
 preparing a composite nickel and copper alloy plating solution containing nickel, copper, self-lubricating particles, hard particles, a cationic surface active agent and sodium saccharate as a hardness raising agent; and 
 supplying an electric current to the solution and the base.  
   
   
   
       13 . The process according to  claim 12 , wherein the electric current is a pulsed current which forms on the base surface an alternate array of nickel and copper alloys layers forming the film.  
   
   
       14 . The process according to  claim 13 , further including the step of roughening the surface of the film to expose the nickel and copper alloys substantially uniformly therein.  
   
   
       15 . The process according to  claim 12 , wherein the self-lubricating particles are of at least one of graphite, hexagonal boron nitride and molybdenum disulfide.  
   
   
       16 . The process according to  claim 12 , wherein the hard particles are of at least one of silicon carbide, silicon nitride, alumina, cubic boron nitride and diamond.  
   
   
       17 . The process according to  claim 12 , wherein the solution contains the self-lubricating particles in the amount of 6×10 −5  to 4.2×10 −3  mol/cm 3 .  
   
   
       18 . The process according to  claim 12 , wherein the solution contains the hard particles in the amount of 7×10 −5  to 5×10 −3  mol/cm 3 .  
   
   
       19 . The process according to  claim 12 , wherein the solution contains the surface active agent in the amount of 5×10 −3  to 1×10 −1  mol/cm 3 .  
   
   
       20 . The process according to  claim 12 , wherein the solution contains the hardness raising agent in the amount of 5×1 0 −6  to 3×10 −5  mol/cm 3 .  
   
   
       21 . The process according to  claim 12 , wherein the solution further contains citric acid, and the electric current is a constant current.  
   
   
       22 . The process according to  claim 21 , wherein the solution contains the self-lubricating particles in the amount of 6×10 −5  to 4.2×10 −3  mol/cm 3 .  
   
   
       23 . The process according to  claim 21 , wherein the solution contains the hard particles in the amount of 7×10 −5  to 5×10 −3  mol/cm 3 .  
   
   
       24 . The process according to  claim 21 , wherein the solution contains the surface active agent in the amount of 5×10 −3  to 1×10 −1  mol/cm 3 .  
   
   
       25 . The process according to  claim 21 , wherein the solution contains the hardness raising agent in the amount of 5×10 −6  to 3×10 −5  mol/cm 3 .